• 물과 미래
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• 제20권3호
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• pp.237-245
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• 1987

경사정지수역으로 유입되는 밀도류의 거동이 흐름의 지배방정식인 연속방정식 운동량보존식 및 추적물수송식에 의하여 수치적으로 해석된다. 최대여행거리와 안정 plunge point는 바닥경사와 유입밀도 Froude 수 $Fr_e$에 지배를 받는다. 또한 그들은 바닥밀도류의 상부나 plunge point의 하류에 형성된 와와 밀접한 관계가 있다. Plunge depth는 바닥경사와 $Fr_e$의 함수이고, 본 수치실험에서 얻은 plunge depth는 발표된 실험자료나 해석해와 비교적 잘 맞았으며 이에 관한 예측식이 유도되었다.

• Journal of Welding and Joining
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• 제34권3호
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• pp.17-22
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• 2016

In terms of mechanical and metallurgical characteristics, the effect of tool plunge depths(0.2, 0.5, 0.7, 1.0, 1.5mm) on weldability in dissimilar Al5083-O/DP590 friction spot joint has been clarified. From the results, it is found that the stirred nugget was stably formed at a plunge depth of more than 0.7mm, which is caused by improved stirring action against each other material. With increasing a plunge depth, the thickness of intermetallic compound(IMC) layer in Al5083-O/DP590 joint has a tendency to increase. The tensile shear strength reaches to the maximum failure load of 6.5kN at a plunge depth of 0.7mm due to relatively small decrease in the thickness of Al5083-O sheet and relatively minute thickness of IMC layer, compared with those of other plunge depth conditions.

• 대한토목학회논문집
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• 제7권4호
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• pp.51-60
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• 1987

음부력(陰浮力)을 갖는 유체가 수평정지수역(水平靜止水域)으로 유입(流入)되어 일어나는 밀도류(密度流)의 거동이 유한차분기법에 의하여 수치적(數値的)으로 해석된다. 정지수역에서 plunge 흐름의 모양은 유입밀도(流入密度) Froude수(數) $Fr_e$에 크게 영향을 받으며 밀도류전면속도(密度流前面速度)는 음부력(陰浮力)의 증가 즉 $Fr_e$의 감소에 따라 증가한다. plunge point의 최대여행거리(最大旅行距離)와 안정(安定) plunge point는 뚜렷하게 무차원시간 T와 $Fr_e$의 함수로 나타난다. 음부력흐름(또는 plunge point)의 좌우에 와(渦)가 큰 규모로 발달된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.417-418
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• 2012

• 대한기계학회논문집A
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• 제23권6호
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• pp.881-894
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• 1999

Cylindrical plunge grinding is widely used for final machining process of precision parts such as automobile, aircraft, measurement units. But in order to make parts which have high precision accuracy and high surface integrity, it is necessary to consider grinding characteristics due to accumulation phenomena of grinding wheel in plunge grinding process. In this study, in order to examine closely plunge grinding process, grinding power, grinding force, real depth of cut are monitored in transient state, steady state and spark out state. As the result, it is shown that grinding power and force are affected by dressing condition, depth of cut and speed ratio and that there exist threshold grinding force and it also affected by dressing condition. Also considered effects of grinding conditions on surface roughness and roundness of workpiece

• International Journal of Precision Engineering and Manufacturing
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• 제7권3호
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• pp.8-13
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• 2006

Plunge milling process is used for machining hole and is widely used in aerospace, automobile, and die/mold industries. The cutter is fed in the direction of spindle axis which has the highest structural rigidity. The kinematics of plunge milling differs from the traditional turning and milling in aspect of tool engagement and chip generation. This paper proposes the mechanistic cutting force model for plunge milling. Uncut chip thickness is calculated using the present cutter edge position and the previous cutter edge position. Instantaneous cutting force coefficients, which depend only on instantaneous uncut chip thickness, are derived based on the mechanistic approach. The developed cutting force model is verified through comparison of the predicted and the measured cutting forces.

• 한국생산제조학회지
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• 제6권1호
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• pp.34-44
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• 1997

This study presents the recursive constraint bounding(RCB) method to reduce the cycle time in internal cylindrical plunge grinding process. This method can cope with process noise as well as modeling bias. The main features of RCB method are its utilization of measurements at the end of each cycle and its use of monotonicity analysis for determining the extremes of bias and noise. This method is investigated in simulation and evaluated by experiment in internal cylindrical plunge grinding operation. The results from simulation and experiment show that it is effective in reducing cycle time in spite of modeling uncertainty in the forms of process noise and modeling bias.

• 한국정밀공학회지
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• 제16권12호
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• pp.54-59
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• 1999

High precision internal plunge grinding is difficult because of the decrease in the quill stiffness due to the small diameter of wheel. In this paper, the characteristics of internal plunge grinding were investigated. Grinding experiments were performed at various grinding conditions with vitrified bonded CBN wheels. The grinding period was assumed to be consisted of rough grinding and fine grinding. The classification of grinding was determined int terms of the normal grinding forces and actual depth of cut. The experimental results indicate that the higher depth of cut and infeed speed result in the longer rough grinding time. The maximum normal grinding force was nearly equal to the static force and it decreases exponentially as the grinding continues.

• 한국산학기술학회논문지
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• 제12권11호
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• pp.4726-4731
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• 2011

본 논문에서는 배치 단위로 이루어지는 플런지연삭의 최적 연삭 조건 선정을 위한 알고리즘을 제안하였다. 제안된 알고리즘은 연삭공정을 나타내는 상태변수를 선정하고 선정된 상태 변수를 바탕으로 각 사이클에서 이루어지는 최적의 연삭 조건을 GA(Genetic Algorithm)를 이용하여 선정하였다. 이를 바탕으로 전체 배치 단위의 최적 연삭조건은 DP(Dynamic Programming)를 이용하여 구하였다. 제안된 알고리즘을 시뮬레이션을 통해 그 가능성을 검증하였다.

• 한국정밀공학회지
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• 제12권9호
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• pp.66-73
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• 1995

This paper presents monitoring and control system to decrease non-production time such as air grinding and partial contact in cylindrical plunge grindings. The 4-stage model of the plunge grinding process is proposed according to the state of contact between grinding wheel and workpiece; air grinding, partial contact, entire contact and spark out. Experimentally it is seen that the AE sensor and ultrasonic sensor are very effective to detect the grinding states. Monitoring and control algorithm using recognized grinding process was introduced and a experiment were conducted to verify the developed system.